In the fluid treatment industry, the formation of scale as a result of minerals precipitating on desalination membranes where reverse osmosis (RO) takes place is a potential problem that may affect the conversion or recovery of product or permeate water (for example) from the available water supply. For these RO systems, and indeed any other membrane based treatment systems, it may be considered desirable that minerals or salts within the water supply are reduced to a much lower concentration than for non membrane based treatment systems. Although nano-filtration, ultra-filtration or micro-filtration membranes reduce particles, organic matter and other contaminants larger than salt and dissolved minerals, the membranes are also subject to mineral scale formations thus reducing permeate or product water flow volumes.
It may be desirable to achieve conversion or recovery of the maximum amount of water as fresh product water at the minimum cost. It is however well recognised that water recovery for RO and productivity of permeate of nano, ultra & micro filtration membrane systems are limited by the precipitation of sparingly soluble solutes including silica, barium sulphate, magnesium, calcium carbonate and calcium sulphate, which can scale and ruin the membranes.
Conventionally, the control of scaling includes the use of: (i) salt regenerating water softeners for the reduction of positively charged scaling minerals such as calcium and magnesium—negatively charged silica and silicon are not removed by this standard cation exchange softener method and require dosing of antiscalant chemicals to protect membranes; (ii) Birm™ media filter which is a media for the reduction of dissolved iron and manganese compounds from raw water supplies or feed water, as well as for green sand filters; it acts as an insoluble catalyst to enhance the reaction between dissolved oxygen and the iron compounds; (iii) acid for the prevention of calcium carbonate scale; and (iv) antiscalant chemicals for keeping the solutes in a supersaturated state.
Although the use of the above chemical techniques are effective, they have the shortcoming in that it is maintenance time consuming and costly to maintain and operate membrane systems affected by mineral scale and requires the installation of cation and anion exchange filtration and ongoing dosing of antiscalant chemicals. For instance, it is difficult and costly to accurately predict the maximum concentrations of the sparingly soluble solutes in excess of recorded solubility limits that can be tolerated with antiscalant chemicals.
Further, in the case of cation exchange softeners, these only work in low salinity applications because higher salt content in the water reduces the positively charged bonding and/or attraction of calcium to the media
Prior known systems have incorporated voltage based signal drive systems for driving signals into coils in an attempt to treat or condition fluid to avoid or remove scaling. However, these systems generally use and/or waste a large amount of power in generating the drive signals, which can lead to problems where the fluid treatment plants are remote from mains power supplies. Further, this problem may be exacerbated when the signals are being driven into low ohmic loads which then require increased power consumption. This can lead to a loss of fluid conditioning in systems that may have a limited power supply.
Further, prior known fluid treatment methods associated with bore holes require ground fluid (e.g. water) to be extracted from a bore hole using a submersible pump. After the water has been extracted, the water may then be treated or conditioned. However, the submersible pump itself may have scale formed therein, thus reducing the capacity of the water being pumped and reducing the working life of the pump itself.
An object of the present invention is to provide one or more improved systems and methods for the conditioning of fluids, or to at least provide the public with a useful choice.
The present invention aims to overcome, or at least alleviate, some or all of the afore-mentioned problems.
Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiment of the invention without placing limitations thereon.
The background discussion (including any potential prior art) is not to be taken as an admission of the common general knowledge in the art in any country. Any references discussed state the assertions of the author of those references and not the assertions of the applicant of this application. As such, the applicant reserves the right to challenge the accuracy and relevance of the references discussed.